Newb needs help with logical volume

I apologize if this issue was brought up before, but to avoid confusion among lots of other questions, I have linked a similar thread at the bottom of this post.

So my issue is: When using "verify disk" in the Disk Utility, the log tells me...

"Invalid Disk Label @ 499239710720: cksum mismatch", yet at the end of the log everything appears to be OK.

Let me start from earlier. I have OS X 10.8.5. I created a back up on my time machine using an external hard drive. I downloaded and installed Yosemite. I decided I didn't like it, so I went to time machine and restored back to 10.8.5.

From my understanding, Yosemite creates a logical volume. I tried using the command:

diskutil cs revert disk1

And I get the error -69741: target disk isn't eligible...

I need to know if the "verify disk" is possible to fix/repair. For lack of a better explanation, I am including some screenshots for reference.

Note: I would rather not have to do a lot of work, such as making a clone of the hard drive and restoring it from an external source... but if it comes down to that please show me how, because this is my first time tinkering with the hard drive.

Also, if you want to restore from a 10.8.5 time machine backup, it might be better to delete the whole lot, reformat - AND THEN do the restore.

diskutil cs delete 5EE283B2-3910-416E-BFE2-FE8B23F1D229

should delete it

Do you have a mountain lion bootable usb? If so, it would be better to boot up from that with the option key, run the command from terminal whilst booted up in that usb and then format the whole drive as Mac OS Extended (Journaled) with Erase in Disk utility. Connect up your time machine backup and restore to your newly formatted drive.

In this way no remnant of yosemite core storage will be left over which seems to be what is happening in your case.

So it is telling you that that disk wasn't a non-Core storage volume before so it has nothing to revert it to. I guess it was created fresh as part of the install.

So you can't revert it, unless you have any other isue I wouldn't bother with the verify disk error, DU doesn't support Core Storage volumes so it doesn't surprise me. Verify disk won't fixe the core storage issue for you.

You could backup all your data the do an internet recovery and download whatever your machine shipped with, then upgrade to Yosemite, then revert the volumes - that will work as the volumes will be standard ones first before being changed into CS.

I don't think he wants yosemite though. It seems he wants to go back to mountain lion.

Click to expand...

Hmmm but he is ML on Core Storage so he will either need to IR and format to normal storage if allowed or go through the full upgrade to Yos, then revert, then resize his partitions as required and install ML from there....I think

Well there are several ways he can go back to mountain lion without the core storage, but I doubt if any of them actually require him to upgrade to yosemite first.

He doesn't necessarily need to revert the system. He can delete the core storage using the delete command I gave, reformat the drive, restore to 10.8.5 from time machine backup or clean install from bootable usb. Internet recovery and recovery partition are also possibilities, but a bootable usb is better.

He already tried the restore from backup, but it seems it is corrupted. Hence my suggestion that he gets rid of the core storage first using the delete command instead of revert, and then reformat the drive. Then he can decide if he wants a clean install or time machine restore.

The screenshots, maybe? Yosemite-style close, minimise and full-screen buttons were hardly a revelation. And the style of the toolbar of Safari was well publicised by Apple. The topic really wasn't about Yosemite, it was about Core Storage (and lack of documentation by Apple). …

Click to expand...

Thankfully parts of the lost content were saved, but it took a long time for those parts to come together. I'll repost some of that content …

Staff Member

Okay so you still have your ML backup on an external Time Machine disk yes?

We are going to need to wipe the disk and restore.

Try this... option key boot to the Time Machine disk and that will get you to a recovery screen. Then go to the Utilities menu and launch Terminal. Now enter the command below. Make sure you include the quotes and all just like I have it here.

Code:

diskutil cs delete "Macintosh HD"

Now quit Terminal and launch Disk Utility. Go to the erase tab and select the drive in the left column. Now select Mac OS Extended (Journaled) in the dropdown then apply that format.

Now quit Disk Utility then click restore and that will put the OS and all your apps and data back on the drive and hopefully get you fixed up.

I am assuming here you did not backup to the TM disk since you installed Yosemite, and that is just a Mountain Lion backup.

I think what got you sideways here is you restored ML to a Yosemite core storage volume.

He already tried the restore from backup, but it seems it is corrupted. Hence my suggestion that he gets rid of the core storage first using the delete command instead of revert, and then reformat the drive. Then he can decide if he wants a clean install or time machine restore.

Click to expand...

I appreciate the insight; it is a possibility that my external back-up may be corrupted… My external hard drive is in a crackpot casing that more or less works every time(example, when I plug in the hard drive, the activity light blinks on and off due to a faulty connection). I was going to invest in a new case for it, but am putting my finances into other things atm.

Hmmm but he is ML on Core Storage so he will either need to IR and format to normal storage if allowed or go through the full upgrade to Yos, then revert, then resize his partitions as required and install ML from there....I think ￼

Click to expand...

You just confused the hell out of me… lol. I think what you are trying to say is that I should upgrade to Yosemite, then revert (which I already did). Resizing the partitions doesn't seem like the thing I should do, though, since I am ultimately trying to figure out how to fix the verify disk/repair disk errors.

I will return later to post my results. Thank you all very much for your input.

I tried the troubleshooting steps. I wound up not doing the delete commands at recovery(explained below), and instead erased my Mac HD, and re-did the restore from my external hard drive time machine. After recovery was finished, I logged back in and did the verify disk, and am now seeing no issues with a verify disk/mismatched check, and everything on the disk appears to be OK.

Here are the two failed commands I tried (at recovery) along with the answer-backs:

Footnote: I don't know how to use Su, or Sudo. I am not sure how to use the Root command from here. Not experienced with command-line stuff. So what does the last answer back mean? I googled the (-69778) error and came up with things about an encrypted hard drive. Not sure if this applies to me.
I wonder if this is relevant; I am still seeing issues with my verify permissions? Do I need to fix this, or leave it alone?

Staff Member

I tried the troubleshooting steps. I wound up not doing the delete commands at recovery(explained below), and instead erased my Mac HD, and re-did the restore from my external hard drive time machine. After recovery was finished, I logged back in and did the verify disk, and am now seeing no issues with a verify disk/mismatched check, and everything on the disk appears to be OK.

Here are the two failed commands I tried (at recovery) along with the answer-backs:

Click to expand...

You left out the quotes in the command I gave you. The error messages are saying there is no core storage (CS) volume by the name(s) you specified.

So you are all fixed up now?

What permissions issues do you see now? There are some that are normal and can be ignored.

Alright, I looked at the first & second link. Does this article mean that verify disk is not affective? Or does it mean that through trial and error, this guy found out that Yosemite is not the cause of the verify disk error?

I don't think the third link applies to me, because I reverted back to my restore?
And the fourth link probably doesn't apply, because I wasn't using partitions before.

When Disk Utility reports that an HFS Plus volume appears to be OK, you can't be certain that the disk/drive is truly OK.

If there was a problem with the disk/drive before you restored data, it may be that the restored data is not in an affected area of the disk.

Disk Utility uses fsck_cs and fsck_hfs but (at least in Mavericks) it can not use fsck_hfs to scan a device for I/O errors.

For a thorough test of a drive I normally use HDAT2. The answer in Ask Different outlines the routine for destruction of data; you'll probably want a nondestructive routine such as read/write/read/compare (R/W/R/C).

As per the screenshot, things seem to be in order now. This was a good learning experience. I don't intend to do extensive research into the monitoring of hard drive health unless I do some school work on it or something... Thanks all!

Where previously there were red alerts about checksum mismatches – signs of possible problems with hardware – now (without Core Storage) there's no such checking.

Abandoning Core Storage might make partitioning easier for non-technical users, but critically: the abandonment reduces the ability of the operating system to check for problems with data. Abandonment causes Disk Utility to do less when verifying a disk, and so on.

Where previously there were red alerts about checksum mismatches  signs of possible problems with hardware  now (without Core Storage) there's no such checking.

Abandoning Core Storage might make partitioning easier for non-technical users, but critically: the abandonment reduces the ability of the operating system to check for problems with data. Abandonment causes Disk Utility to do less when verifying a disk, and so on.

Click to expand...

Core Storage is fine if either your boot partition is the only partition on the boot drive or you never want to easily amend/change the partitions on that drive. If you want to ever change partitions on a CS drive the DU can't do it, that is a serious error on Apple's part IMHO.

For instance I have a backup bootable partition (50GB) on my 1TB HDD (prime boot is my SSD. Installing that partition the Yosemite installer converts the entire HDD to CS....

Until they ship a CS management utility then this is a serious hassle.

Hey all - I have this issue also, and not sure if I really need to do something about it? I've been researching this for a few weeks, and saw the other thread where you guys discovered this back in June. Should I go through the motion of fixing, or will I make it worse if/when Apple makes a change to address this?

Here is my specific deal - 13 inch Macbook air, mid 2012, 8gb, 500hd.

- Installed Mavericks over ML, then started having shutdown stall errors. It did take longer to shutdown.

- In Aug, gave up trying to find fix for the shutdown, did erase and reinstall. Shutdown problem fixed.

- Few weeks after Yosemite release did install over Mavericks. Mac wasn't acting right, so week later did erase and reinstall. This was the first time I noticed the changes in DU.

Long story short, did a 2nd erase and reinstall with Yosemite, found my mail in Saved on my Mac did transfer over and were missing. Found TM backups weren't including the user library folder in any backup since 8/16/14 (which is about the time I did the first erase reinstall with Mavericks to solve the shutdown error). So this week I just did a restore with my backup and selected 8/16 as the date as way to get those emails back. All worked, and I am back in Mavericks.

Now back in Mavericks, I still have DU showing HD as Logical Volume. I have the shutdown error problem again, but overall the Mac is working fine.

Staff Member

There is nothing wrong with having core storage activated. Yosemite is doing this by default on some newer systems. It just prevents some operations in Disk utility. Nobody quite knows why Apple has done this yet, just some guesses.

Yes, I would try to turn off core storage with the command below then try and repair the disk in from recovery in Disk Utility.

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